U.S. patent application number 11/652854 was filed with the patent office on 2007-07-19 for optical sensor device.
This patent application is currently assigned to TRW Automotive Electronics & Components GmbH & Co. KG. Invention is credited to Ulrich Backes, Ulf Mordau.
Application Number | 20070165232 11/652854 |
Document ID | / |
Family ID | 37898824 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070165232 |
Kind Code |
A1 |
Mordau; Ulf ; et
al. |
July 19, 2007 |
Optical sensor device
Abstract
An optical sensor device includes a photoconductor structure
having first and second partial members (16, 18) and a coupling
surface (20) for coupling the optical sensor device to an opposing
counter surface of a pane (22), particularly a windscreen of a
motor vehicle. The optical sensor device further includes an
optical transmitter (10) coupling a beam of rays into the first
partial member (16), an optical receiver (12) receiveing a beam of
rays emerging from the second partial member (18), and a printed
circuit board (14) arranged parallel to the coupling surface (20).
The transmitter (10) and the receiver (12) are arranged on the
printed circuit board (14). The photoconductor structure is
designed so that the central ray (28) of the transmitter (10)
enters into the first partial member (16) perpendicularly to the
coupling surface (20) and emerges from the second partial member
(18) perpendicularly to the coupling surface (20).
Inventors: |
Mordau; Ulf; (Reisslingen,
DE) ; Backes; Ulrich; (Radolfzell, DE) |
Correspondence
Address: |
TAROLLI, SUNDHEIM, COVELL & TUMMINO L.L.P.
1300 EAST NINTH STREET, SUITE 1700
CLEVEVLAND
OH
44114
US
|
Assignee: |
TRW Automotive Electronics &
Components GmbH & Co. KG
|
Family ID: |
37898824 |
Appl. No.: |
11/652854 |
Filed: |
January 12, 2007 |
Current U.S.
Class: |
356/445 |
Current CPC
Class: |
B60S 1/0837 20130101;
G01N 21/552 20130101; B60S 1/0888 20130101; B60S 1/0822
20130101 |
Class at
Publication: |
356/445 |
International
Class: |
G01N 21/55 20060101
G01N021/55 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2006 |
DE |
20 2006 000 742.3 |
Claims
1. An optical sensor device, comprising a photoconductor structure
having first and second partial members and a coupling surface for
coupling the optical sensor device to an opposing counter surface
of a pane, particularly a windscreen of a motor vehicle, an optical
transmitter coupling a beam of rays into the first partial member,
an optical receiver receiving a beam of rays emerging from the
second partial member, and a printed circuit board arranged
parallel to the coupling surface, the transmitter and the receiver
being arranged on the printed circuit board, the photoconductor
structure being designed so that the central ray of the transmitter
enters into the first partial member perpendicularly to the
coupling surface and emerges from the second partial member
perpendicularly to the coupling surface.
2. The sensor device according to claim 1, wherein the central ray
of the transmitter is oriented parallel to the coupling surface
after a first total reflection in the first partial member of the
photoconductor structure.
3. The sensor device according to claim 2, wherein the central ray
of the transmitter is oriented parallel to the coupling surface
after a first total reflection in the second partial member of the
photoconductor structure and is oriented perpendicularly to the
coupling surface after a second total reflection.
4. The sensor device according to claim 1, wherein on the first
partial member a first aspherical lens is formed-on opposite the
transmitter.
5. The sensor device according to claim 1, wherein on the second
partial member a second apspherical lens is formed-on opposite the
receiver.
6. The sensor device according to claim 1, wherein the two partial
members form a continuous photoconductor body made of transparent
plastic material.
7. The sensor device according to claim 1, wherein the central ray
of the transmitter undergoes a single total reflection on the pane.
Description
TECHNICAL FIELD
[0001] The invention relates to an optical sensor device.
BACKGROUND OF THE INVENTION
[0002] An optical sensor device comprising a photoconductor
structure having first and second partial members and a coupling
surface for coupling the optical sensor device to an opposing
counter surface of a pane, particularly a windscreen of a motor
vehicle, an optical transmitter coupling a beam of rays into the
first partial member, an optical receiver receiveing a beam of rays
emerging from the second partial member, and a printed circuit
board on which the transmitter and the receiver are arranged, is
known from EP 0 833 764 B1. In this known device, the printed
circuit board is arranged perpendicularly to the windscreen of a
motor vehicle. The beam of light which is emitted from the
transmitter parallel to the plane of the windscreen is coupled into
the windscreen via an input section of a radiation conductor. To do
this, the beam of light is initially deflected at a first
deflection surface through 90 degrees in a direction parallel to
the printed circuit board, before it emerges from the input section
and enters into the windscreen via two further deflection surfaces
through a coupling surface arranged parallel to the windscreen.
After several reflections in the windscreen, the beam of light
emerges from the windscreen and is directed onto the receiver on
the printed circuit board via an output section formed
symmetrically to the input section.
[0003] It is an object of the invention to provide an optical
sensor device with a simpler and more compact construction which is
able to be produced at a more favourable cost.
SUMMARY OF THE INVENTION
[0004] According to the invention, an optical sensor device
comprises a photoconductor structure having first and second
partial members and a coupling surface for coupling the optical
sensor device to an opposing counter surface of a pane,
particularly a windscreen of a motor vehicle. The optical sensor
device further comprises an optical transmitter coupling a beam of
rays into the first partial member, an optical receiver receiveing
a beam of rays emerging from the second partial member, and a
printed circuit board arranged parallel to the coupling surface.
The transmitter and the receiver are arranged on the printed
circuit board. The photoconductor structure is designed so that the
central ray of the transmitter enters into the first partial member
perpendicularly to the coupling surface and emerges from the second
partial member perpendicularly to the coupling surface. The
arrangement of the printed circuit board with the transmitter and
the receiver in accordance with the invention not only saves
structural space in the direction perpendicular to the windscreen,
but in addition makes possible a construction with fewer deflection
surfaces. Compared with the construction known from EP 0 833 764
B1, in which the beam of light emitted from the transmitter is
deflected three times before it enters into the windscreen, only
two deflection surfaces are necessary in the construction according
to the invention. The same applies to the directing of beams to the
receiver after emergence from the windscreen.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 shows an unfolded two-dimensional illustration of the
optical components of a sensor device according to the
invention;
[0006] FIGS. 2a, 2b show sectional views of the sensor device
according to the invention with different kinds of coupling to a
pane; and
[0007] FIG. 3 shows an exploded view of the sensor device of FIG.
2a.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0008] An unfolded two-dimensional illustration of the optical
components of a sensor device is shown in FIG. 1, i.e. FIG. 1 is
not a conventional sectional view. The unfolded illustration was
selected because the basic structure of the sensor device and the
path of rays can be seen better therein than in a sectional
illustration. In addition, the actual three-dimensional form of the
sensor device is not essential for the invention.
[0009] The sensor device has an optical transmitter 10 and an
optical receiver 12 in the form of an infrared transmission diode
and an infrared reception diode respectively, which are arranged on
a printed circuit board 14 (not illustrated in FIG. 1). A
photoconductor structure is basically made up of two identically
constructed partial members 16, 18 which together form a
symmetrical continuous photoconductor body made of transparent
plastic material. The photoconductor structure is coupled with a
coupling surface 20 to an opposing counter surface of a pane 22.
The contact surface 20 is arranged parallel to the printed circuit
board 14 carrying the transmitter 10 and the receiver 12, so that
the printed circuit board 14 likewise extends in a plane parallel
to the pane 22. An aspherical lens 24 is formed on the end of the
first partial member 16 facing the transmitter 10, i.e. the said
lens faces the transmitter 10. A second aspherical lens 26 is
formed on the second partial member 18 and faces the receiver
12.
[0010] A beam of light emitted from the transmitter 10 enters into
the first partial member 16 of the photoconductor structure through
the first aspherical lens 24. Of this beam only the central ray 28,
which enters into the first partial member 16 in a direction
perpendicular to the coupling surface 20, will be discussed at this
time. The central ray 28 is deflected under total reflection
through 90 degrees at a first deflection surface 30 which is
inclined at a 45 degree angle to the central ray 28, so that the
said ray is oriented parallel to the coupling surface 20. After a
further total reflection at a second deflection surface 32 which
faces the first deflection surface 30 and is inclined at a specific
acute angle .alpha. to the coupling surface 20, the central ray 28
emerges from the first partial member 16 through the coupling
surface 20 and enters into the pane 22 under a defined entry angle
.beta..
[0011] The central ray 28 undergoes a single total reflection on
the inner surface of the pane 22 opposite the coupling surface 20,
and emerges from the pane 22 at an exit angle .gamma., which
corresponds to the entry angle .beta., and arrives through the
coupling surface 20 into the second partial member 18 of the
photoconductor structure. Owing to the symmetrical construction of
the photoconductor structure, the path of rays in the second
partial member 18 is symmetrical to the path of rays in the first
partial member 16, i.e. the central ray 28 is oriented parallel to
the coupling surface 20 after a first total reflection on a third
deflection surface 34, and is oriented perpendicularly to the
coupling surface 20 after a second total reflection on a fourth
deflection surface 36. The central ray 28 therefore emerges from
the second partial member 18 perpendicularly to the coupling
surface 20 through the second aspherical lens 26 and strikes onto
the receiver 12 which is arranged on the printed circuit board
14.
[0012] In FIG. 1 also the path of rays of two peripheral rays 38,
40 of the light beam is illustrated. The first aspherical lens 24
ensures that all the rays of the light beam enter into the first
partial member 16 parallel to the central ray 28. In the
photoconductor structure and in the pane 22, all the rays undergo
the same five total reflections (two in the first partial member
16, one in the pane 22 and two in the second partial member 18),
like the central ray 28. The second aspherical lens 26 on the
second partial member 8 bundles together the light rays emerging
from the photoconductor structure, so that all the rays are
directed to the receiver 12.
[0013] In FIGS. 2a and 2b two variants of the coupling of the
sensor device to the pane 22 are shown. According to the variant of
FIG. 2a, an elastic cushion 42 is provided between the sensor
device and the pane 22, whereas in the variant of FIG. 2b a
structure coupler 46, which is fastened to the housing 44 of the
sensor device, is glued onto the pane 22.
[0014] FIG. 3 shows the individual parts of the sensor device of
FIG. 2a. The printed circuit board 14 and two sets of the optical
components described above are accommodated in the housing 44,
which includes a housing part 48 facing the elastic cushion 42 and
the pane 22, and a cover 50. According to the two sets of optical
components, two transmitters 20 and two receives 12 are arranged on
the printed circuit board 14.
[0015] The optical sensor device is particularly suitable, but not
exclusively, as a rain sensor which can be arranged on the
windscreen of a motor vehicle.
* * * * *